[#2] Pass gfx structs by const ref (gfx::Rect, gfx::RectF)

cc/resources/picture_layer_tiling.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_RESOURCES_PICTURE_LAYER_TILING_H_
 #define CC_RESOURCES_PICTURE_LAYER_TILING_H_
 
 #include <utility>
 #include <vector>
 
@@ skipping 10 matching lines @@
 namespace cc {
 
 class PictureLayerTiling;
 
 class CC_EXPORT PictureLayerTilingClient {
  public:
   // Create a tile at the given content_rect (in the contents scale of the
   // tiling) This might return null if the client cannot create such a tile.
   virtual scoped_refptr<Tile> CreateTile(
     PictureLayerTiling* tiling,
-    gfx::Rect content_rect) = 0;
+    const gfx::Rect& content_rect) = 0;
   virtual void UpdatePile(Tile* tile) = 0;
   virtual gfx::Size CalculateTileSize(
     gfx::Size content_bounds) const = 0;
   virtual const Region* GetInvalidation() = 0;
   virtual const PictureLayerTiling* GetTwinTiling(
       const PictureLayerTiling* tiling) const = 0;
 
  protected:
   virtual ~PictureLayerTilingClient() {}
 };
@@ skipping 40 matching lines @@
 
   // Iterate over all tiles to fill content_rect.  Even if tiles are invalid
   // (i.e. no valid resource) this tiling should still iterate over them.
   // The union of all geometry_rect calls for each element iterated over should
   // exactly equal content_rect and no two geometry_rects should intersect.
   class CC_EXPORT CoverageIterator {
    public:
     CoverageIterator();
     CoverageIterator(const PictureLayerTiling* tiling,
         float dest_scale,
-        gfx::Rect rect);
+        const gfx::Rect& rect);
     ~CoverageIterator();
 
     // Visible rect (no borders), always in the space of content_rect,
     // regardless of the contents scale of the tiling.
     gfx::Rect geometry_rect() const;
     // Texture rect (in texels) for geometry_rect
     gfx::RectF texture_rect() const;
     gfx::Size texture_size() const;
 
     // Full rect (including borders) of the current tile, always in the space
@@ skipping 19 matching lines @@
     int tile_i_;
     int tile_j_;
     int left_;
     int top_;
     int right_;
     int bottom_;
 
     friend class PictureLayerTiling;
   };
 
-  Region OpaqueRegionInContentRect(gfx::Rect content_rect) const;
+  Region OpaqueRegionInContentRect(const gfx::Rect& content_rect) const;
 
   void Reset();
 
   void UpdateTilePriorities(
       WhichTree tree,
       gfx::Size device_viewport,
-      gfx::Rect viewport_in_layer_space,
-      gfx::Rect visible_layer_rect,
+      const gfx::Rect& viewport_in_layer_space,
+      const gfx::Rect& visible_layer_rect,
       gfx::Size last_layer_bounds,
       gfx::Size current_layer_bounds,
       float last_layer_contents_scale,
       float current_layer_contents_scale,
       const gfx::Transform& last_screen_transform,
       const gfx::Transform& current_screen_transform,
       double current_frame_time_in_seconds,
       size_t max_tiles_for_interest_area);
 
   // Copies the src_tree priority into the dst_tree priority for all tiles.
@@ skipping 21 matching lines @@
     RectExpansionCache();
 
     gfx::Rect previous_start;
     gfx::Rect previous_bounds;
     gfx::Rect previous_result;
     int64 previous_target;
   };
 
   static
   gfx::Rect ExpandRectEquallyToAreaBoundedBy(
-      gfx::Rect starting_rect,
+      const gfx::Rect& starting_rect,
       int64 target_area,
-      gfx::Rect bounding_rect,
+      const gfx::Rect& bounding_rect,
       RectExpansionCache* cache);
 
   bool has_ever_been_updated() const {
     return last_impl_frame_time_in_seconds_ != 0.0;
   }
 
  protected:
   typedef std::pair<int, int> TileMapKey;
   typedef base::hash_map<TileMapKey, scoped_refptr<Tile> > TileMap;
 
   PictureLayerTiling(float contents_scale,
                      gfx::Size layer_bounds,
                      PictureLayerTilingClient* client);
-  void SetLiveTilesRect(gfx::Rect live_tiles_rect);
+  void SetLiveTilesRect(const gfx::Rect& live_tiles_rect);
   void CreateTile(int i, int j, const PictureLayerTiling* twin_tiling);
 
   // Given properties.
   float contents_scale_;
   gfx::Size layer_bounds_;
   TileResolution resolution_;
   PictureLayerTilingClient* client_;
 
   // Internal data.
   TilingData tiling_data_;
   TileMap tiles_;  // It is not legal to have a NULL tile in the tiles_ map.
   gfx::Rect live_tiles_rect_;
 
   // State saved for computing velocities based upon finite differences.
   double last_impl_frame_time_in_seconds_;
 
   friend class CoverageIterator;
 
  private:
   DISALLOW_ASSIGN(PictureLayerTiling);
 
   RectExpansionCache expansion_cache_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PICTURE_LAYER_TILING_H_